Teratozoospermia (Abnormal Sperm Morphology)

What is teratozoospermia?

Teratozoospermia means a high proportion of sperm have an abnormal shape (morphology). Sperm are assessed under strict criteria that look closely at the head, midpiece and tail. Even in fertile men most sperm look imperfect, so the WHO 2021 lower reference limit is only 4 percent normal forms. A result below 4 percent is called teratozoospermia. When it occurs together with low count and poor motility, it is called oligoasthenoteratozoospermia (OAT).

Symptoms and signs

Abnormal morphology causes no symptoms. It is found on a semen analysis, usually after a couple has had difficulty conceiving. Signs of an underlying cause, such as a varicocele or testicular problem, may sometimes be present.

Causes and risk factors

• Varicocele
• Smoking, heavy alcohol use and recreational drugs
• Obesity and poorly controlled diabetes
• Heat exposure and fever in the previous few months
• Infections of the genital tract
• Exposure to pesticides, heavy metals or other toxins
• Hormonal problems
• Rare genetic conditions, such as globozoospermia (round-headed sperm without the cap needed to penetrate the egg) or macrocephalic sperm

How it is diagnosed

• Semen analysis with strict morphology assessment by a trained laboratory; results are best confirmed on a repeat sample
• Assessment of count, motility and vitality at the same time
• Physical examination and scrotal ultrasound if needed
• Hormone tests where indicated
• Sperm DNA fragmentation testing in selected cases
• Genetic testing if a specific uniform defect such as globozoospermia is seen

Treatment options

Lifestyle and treating the cause

Stopping smoking, reducing alcohol, losing excess weight, avoiding heat and treating infections can improve sperm health over about 2 to 3 months. A clinically significant varicocele may be repaired when other semen parameters are also abnormal. Antioxidants are sometimes used, but evidence for improved pregnancy rates is limited.

IUI

Low morphology on its own is a weak predictor of fertility. If count and motility are adequate, natural conception or IUI may still be reasonable, especially for younger couples.

IVF with ICSI

ICSI is recommended when teratozoospermia occurs with other sperm problems, after failed IUI, or when there was poor fertilisation in a previous IVF cycle. The embryologist chooses the best-looking sperm to inject into each egg. Men with globozoospermia usually need ICSI, sometimes with assisted oocyte activation.

Chances of pregnancy

Isolated low morphology often has only a modest effect on fertility, and many couples conceive. When it is part of a wider sperm problem, ICSI offers a good route to fertilisation. The final chance depends largely on the female partner's age and ovarian reserve, and no treatment can guarantee pregnancy.

When to see a fertility specialist

See a specialist if your semen report shows low normal forms together with other abnormalities, if you have tried for 12 months, or sooner if your partner is 35 or older. A specialist can interpret the result in context and avoid unnecessary treatment. Iswarya Fertility has 91+ centres offering semen analysis and male fertility care.